With the increased production of offshore oil wells, coiled tubing operations are more and more frequently performed on floating vessels or boats. Not surprisingly, such operations encounter many problems that do not occur on land wells. One such example is the movement of on deck equipment caused by waves. Specifically, the heave effect caused by waves can have serious adverse effects on the mechanical integrity of coiled tubing when run from a floating vessel.
This effect is particularly severe in offshore deep well applications, where the acceleration due to a heave of the floating vessel can induce significant tensile loading on the coiled tubing. In situations where a coiled tubing string is working close to its combined stress limit, the effect of heave could cause the coiled tubing string to work beyond its safe working limit, potentially resulting in catastrophic failure. Failure of such nature is typically costly due to the offshore environment of the operation, the loss of production time, and/or the replacement/repair of damaged equipment, for example.
Accordingly, a need exists for a coiled tubing assembly having a control system capable of mitigating the effect of heave for offshore coiled tubing operations performed on a floating vessel.